The nine notorious killers and wanna-be’s rounded up in Stephen Sondheim and John Weidman’s musical Assassins (★★★★☆) all have a gun and a dream. And, as they sing at the show’s start, “Everybody’s got the right to their dreams” in this here America. That they also have a right to their guns isn’t sung, but understood, as each of them raises a pistol towards the audience in director Eric Schaeffer’s first-class production at Signature Theatre.

Set inside a ghostly recreation of Ford’s Theatre, Schaeffer’s staging raises pistols and controversial questions, and still has a good laugh at the harrowing thought that any bad actor with a gun and a dream can change the course of history.

The show builds on the sound notion that Lincoln’s assassin John Wilkes Booth (Vincent Kempski) fired a shot that still ricochets through society in the form of infamy for lone gunmen. Booth’s success as a murderer might have created an endless loop of shooters who in turn inspire future shooters to express their aspirations and anger, or inflict their will, by becoming gun-wielding assassins.

Summoned to this exquisitely decrepit Ford’s by the theater’s guyliner-sporting Proprietor (Kurt Boehm), the assassins egg each other on to sing and say their piece about what led them to follow in Booth’s footsteps.

Kempski’s florid performance as florid thespian Booth takes a moment’s getting used to, but grabs hold in its tangy sense of humor and twangy Southern theatricality. He sings the part well, too, with Booth assuming a vaunted position as patron saint to this ensemble of unstable Macks and Mabels. Godfather of modern assassins, he sounds like an expert extolling the virtues of pulling the trigger in “The Gun Song,” joined by President Garfield’s killer, Charles Guiteau (Bobby Smith), and McKinley’s murderer, Leon Czolgosz (Lawrence Redmond).

Would-be assassin of President Ford, Sara Jane Moore (Tracy Lynn Olivera) also sings along, dreaming about the statement she could make with a gun. Moore is one of the shooters in Assassins who failed in her aim to take down a president, although, in this crowd, even the ones who failed miserably are remembered and respected for taking their shot. So while Sondheim’s sharp lyrics, and Olivera’s wide-eyed expressiveness, make great comedy of Moore’s foibles, the story never loses sight of the seriousness of what she set out to do.

Assassins — Photo: Christopher Mueller

The entire premise, the score, the costumes, and the performances of this Assassins teeter on a dagger’s edge between a morbid fascination with a killer’s mentality, and the cast’s mordant delivery — as in Smith’s charmingly deluded Guiteau. Smith’s superb timing sells the joke that Guiteau can hold the room’s attention just by waving his weapon. And alternately, his superb timing relays the sober reminder that some jokers kill for that sort of attention. When Moore and Lynette “Squeaky” Fromme (Rachel Zampelli) bond like giggling schoolkids over the fact that they both knew an intense dude from West Virginia named Charlie, the audience can indulge a boisterous laugh with them, and at them, still woefully aware they’re referencing a mass murderer who’d put any of this lot to shame.

Schaeffer guides the company surely along the precarious edge, and, bolstered by music director Jon Kalbfleisch’s solid orchestra, the cast serves up Sondheim’s score with the right touch of showmanship to soften the show’s piercing blows. The lead cast, and a stacked chorus quintet — including Nova Y. Payton, Maria Rizzo, and Jimmy Mavrikes — spin through this soundtrack of broken dreams, reflecting myriad styles from barber shop to showtunes to spirituals. Sam Ludwig aptly captures an air of nostalgia in his pleasing vocals as the assassins’ Balladeer, then shades that all-American innocence with a hint of something sinister in his riveting turn as Lee Harvey Oswald.

Sinister, or simply unwell, the assassins tend to rhapsodize about their outsized ambitions, and even about their guns, though not much about their politics. In fact, this winking production, Signature’s third mounting of Assassins, adroitly sidesteps partisan arguments by focusing on the impartial power of a gun to affect anybody (or any body). Especially in the hands of a shooter madly determined to prove their worth to the world, to their comrades, or just to Jodie Foster, the gun transcends politics. It’s a tool for the Everyman or for any woman or ideology, it’s protector and projector of the American dream, upholder of law or igniter of anarchy.

The joke and the truth of Sondheim and Weidman’s prescient ode to the power of one finger on the trigger is that the gun is the uncredited main character of Assassins. The show seems to suggest that the gun might be the principal character of American history, once all the ballads have been written.